The present invention relates generally to a method and apparatus for the installation and removal of rubber track belts on a vehicle or machine, for manufacture of the vehicle or service of either the vehicle or the track.
Continuous rubber tracks are used to propel vehicles or machines. In particular, the use of such tracks has found success in the agricultural field. These tracks have several advantages over other forms of propulsion and are desirable as a mode of travel. One of the known advantages is in distributing the weight of the load a vehicle may carry. This facilitates travel when the ground is wet and reduces undesirable soil compaction. Another advantage is the greater traction allowed by having a greater surface contact area with the traveling surface, which is useful for pulling farm implements.
Such tracks are typically trained around a set of wheels. Motive force is transmitted to the track in a desired manner. Typically, at least one of the wheels in contact with the track is driven, causing the vehicle to travel. In one embodiment, these wheels are separable about their circumference allowing the wheel to be split into halves. This assists in facilitating the installation and removal of the tracks, particularly with a track having a central, inwardly extending circumferential rib. The wheels separate along a circumferential groove typically located at the center of the width of each wheel. This groove allows the track to stay aligned on the otherwise flat surface of the wheel. When the outer half of each wheel is removed from a particular side of the vehicle, the track is ready for installation or removal.
However, the flexible rubber tracks for large farm tractors are very large and very heavy (sometimes in excess of several thousand pounds). Consequently, such tracks are cumbersome and can be dangerous to work with. For example, the width of the tread may be up to three feet across. Such tracks are particularly difficult to handle. Unlike rigid components that can easily be lifted and placed with standard work equipment such as hoists, flexible tracks may assume many different undesirable shapes as different forces are applied. For example, the tracks are typically banded together and once a track is unbanded it may fall over if not handled properly. To lift the track and maintain and/or achieve the desired shape of the track is difficult and requires considerable manpower and time.
Prior to the present invention, the track was removed and installed with cumbersome chains and hoists. One method was to use another lifting vehicle in combination with chains and at least several workers to shape the track and force it into place onto the desired vehicle or machine. This procedure has many drawbacks. One drawback is the risk of damaging the track. In addition, that procedure is labor intensive and relatively dangerous. Another method of installation or removal uses a specific fixed, rigid frame to drape the track around it and then place it onto the vehicle. These frames, being of a fixed and rigid shape are of limited capability and generally cannot be used for another size track or for a different vehicle. In addition, the track must be shaped, manually or by machine, to allow the track to fit around the static frame. This rigid frame is further limited by a lack of maneuverability and versatility for installation or removal. Chains are attached to the sides of this frame when needed to pick the frame up and maneuver it into position to place or remove a track. This device was also complicated with many independently adjustable fasteners, bolts, hooks, slots and brackets.
A need exists for a versatile, safe and efficient way to install and remove rubber tracks on vehicles, particularly on large vehicles such as large track driven farm tractors.
In accordance with one aspect of the invention, an apparatus for installing a continuous track onto a track driven vehicle or a portion of the vehicle is provided. The apparatus includes a first curved track engaging member and a second curved track engaging member having an adjustable curvature. An elongated member connects the first and second curved track engaging members in opposed relation with the elongated member being of an adjustable length to permit the distance between the first and second curved track engaging members to be adjusted.
In accordance with one aspect of the invention, the first curved track engaging member has a curvature that approximates the installed curvature of that portion of the track engaged by the first curved track engaging member and the adjustable second curved track engaging member, when adjusted to a desired curvature, can approximate the installed curvature of that portion of the track engaged by the second curved track engaging member. These may correspond to rear and front or front and rear portions of the installed track, respectively. The second curved track engaging member may be composed of a pivot arm curved to approximate the installed curvature of that portion of the track engaged by the pivot arm when extended to a desired degree.
In accordance with one embodiment of the invention, the pivot arm has a pivotal connection to the second curved track engaging member that selectively extends and retracts by extension of a retractable cylinder that is capable of driving the pivot arm to cause the pivot arm to pivot and move inwardly or outwardly, respectively, in response to retraction or extension of the cylinder.
The elongated member may have at least one selectively retractable and extendable cylinder connected to one curved track engaging member at opposed ends to permit extension or retraction of the curved track engaging member so that when it is adjusted to a desired curvature it can approximate the installed curvature of that portion of the track engaged by the respective extended or retracted curved track engaging member.
In accordance with another aspect of the present invention, an apparatus for installing a continuous track onto a track driven vehicle or portion thereof is provided.
In accordance with another aspect of the invention, the apparatus for installing a continuous track includes a lift point structure that preferably is longitudinally adjustable so that when it is longitudinally adjusted to a desired position the location of an allowable lengthwise balance at or near the center of gravity in the lengthwise vertical plane of the elongated member is approximated when the apparatus is engaged or carries the track thereon. In addition, the lift point structure may be transversely or perpendicularly adjustable relative to the length of the elongated member to permit adjustment to a desired position that approximates the location of a desired balance at or near the center of gravity in the perpendicular direction relative to the length of the elongated member. This permits a combination of tracks of various sizes. The support structure can be of a C-shaped, gooseneck configuration or any other desired configuration or shape.
In accordance with one aspect of the invention, a flexible track is placed onto or removed from a vehicle using an apparatus as previously described, which may have adjustable arms allowing the configuration of the apparatus to approximate the shape of the installed shape of the track to facilitate the installation or removal of the track. Extendible and retractable cylinders may be used for articulation of the arms on the apparatus either extending away from the body of the apparatus or retracting towards the body of the apparatus. Advantageously, a single operator utilizing a hand-held control device may centrally control these retractable cylinders. In one embodiment, two linearly extending opposing arms connected by an elongated member are provided. One of these opposing arms has an additional pivot arm that rotates about a point located on the same opposing arm. This dual motion arm, which is attached to the elongated member on one end and the pivot arm on the other, is contemplated in this embodiment to assist in the installation or removal of the track onto or from a larger wheel on the vehicle. The opposing arm to the dual motion arm can be used to assist in the installation or removal of the track onto or from a smaller wheel on the vehicle. These arms can either be extended or retracted for a desired task. Also, various shapes and sizes of tracks, in width or length, can be accommodated by the adjustment of the apparatus. Further, the center of gravity of the device and track draped thereon can be adjusted by the adjustment of these cylinders to assist in the installation or removal of the engaged track onto or from the vehicle. The center of gravity also can be adjusted by the adjustment of lift point structure allowing for a different installation shape, a different length of track or a different width of track to remain engaged with the apparatus to facilitate installation or removal onto or away from the vehicle. The tracks are readily installed or removed using the apparatus with a minimum of manpower and effort and without damage to the vehicle.
In accordance with the method and apparatus aspects of the invention, a flexible track is placed onto or removed from a vehicle using an apparatus with only two opposing arms extending linearly or pivotally or any combination of the two. The pivot arm may or may not be present in this embodiment. Thus, in one aspect, the two curved end members are permanently curved to a desired curvature that approximates the installed end curvatures of the track. For example, a vehicle with a larger rear wheel and a smaller front wheel would utilize an apparatus with opposing front and back curvatures that approximated the curvature of the rear wheel and the front wheel, respectively. The track would be engaged by the linear extension of the curved arm portions of the apparatus for either removal or installation. The controls can be similar to those described in the first embodiment.
In accordance with another aspect of the present invention, the lift point structure can be of a desired shape and/or configuration to overcome different physical interferences with the installation or removal of the track. For example, a vehicle may have an oversized fender to cover the track that may not allow the current design of the lift point structure to maneuver to a point where the apparatus could engage the track. Further, once the track is installed onto the vehicle and modifications are made to the tractor""s appearance or structure, either in the field or in subsequent manufacturing steps, a lifting device used for installation may not be useful for removal. This embodiment contemplates a lift point structure that is able to overcome these problems.
In accordance with yet another aspect of the invention the apparatus may take on a shape that is designed to accommodate certain vehicles with varying physical obstacles to the installation or removal of the track. For example, a mechanism that is necessary to the operation of the vehicle may protrude from the vehicle interfering with and limiting the space with which to engage the track. This embodiment would make changes to the shape of the apparatus to allow the ease of removal or installation in such circumstances.